Effect of nano-composite repair fluid on electrical tree growth under different conditions in cables

Electric trees have been the main types of cable defects that lead to cable insulation failure and power transmission interruption. The electrical tree repair technology can reshape the cable insulation performance to a certain extent and avoid the characteristics of power transmission interruption, which makes it widely used in the future. Existing research mainly focuses on repairing electric tree in the way of pre-injection of insulation material in the early stage of the cable, which cannot achieve the suppression or repair of electric tree in the cable. It is of high research value to explore new and reliable methods for suppressing electrical trees in transport cables from the perspective of repair engineering technology. This paper first sets up a cable accelerated aging experiment platform, prepares two sets of dry electric tree and wet electric tree samples, and sets up a cable repair platform in the laboratory environment to inject nanocomposite repair fluid. Comparing the characteristic parameters of each electric tree sample before and after the injection of repair liquid, the influence law of nano-composite repair liquid injection on the growth of the electric trees in the cable was analyzed. The results show that: after injecting the repair liquid, the growth of the electric tree was suppressed and the maximum discharge was reduced, and the suppression effect of the wet electric tree was the most obvious; According to the measurement characteristics, it was found that the initial discharge voltage of the electric tree sample injected with the composite repair solution was too large, the maximum discharge amount was small, but neither could reach the insulation level of the new sample. That was to say, the water tree repair liquid has an inhibitory effect on the growth of the electric tree, and the nano-composite repair liquid has a more obvious inhibitory effect on the electric tree. Finally, the mechanism of the inhibition effect of nano-composite repair liquid on the growth of electrical trees in different states is summarized.